A rare case of perianal granular cell tumor: case report and literature review.

Granular cell tumor (GCT) is a rare submucosal neoplasm most commonly localized in the oral mucosa; with one-third of all cases found in the tongue, with less than 30 cases of perianal GCT reported in the literature, making it a rare anal neoplasm. Wide local excision is the gold standard of treatment and follow-up includes annual colonoscopy due to the high incidence of reoccurrence. Here we describe a rare case of benign perianal GCT in a 29-year-old female who presented asymptomatically; however, pathology report revealed a S100 positive immunostaining pattern. GCT is an important differential to be included when evaluating a patient with an asymptomatic perianal submucosal lesion. Since GCT and Squamous Cell Carcinoma present with similar pseudoepitheliomatous hyperplasia of the epithelium it is important that a biopsy and immunohistochemical analysis be performed to allow for accurate diagnosis and appropriate treatment.